The invention relates to a data carrier comprising a coil with two coil terminals and an integrated circuit, said integrated circuit comprising an integrated main capacitor which is connected to two contacts of the integrated circuit, each contact of said two contacts being connected in an electrically conducting manner to a coil terminal via an electrically conducting connection.
The invention also relates to a module comprising coil terminals to which a coil is connectable, which module comprises an integrated circuit, said integrated circuit comprising an integrated main capacitor which is connected to two contacts of the integrated circuit, each contact of said two contacts being connected in an electrically conducting manner to a coil terminal via an electrically conducting connection.
The invention further relates to an integrated circuit for a data carrier comprising a coil with two coil terminals and an integrated circuit, said integrated circuit comprising an integrated main capacitor which is connected to two contacts of the integrated circuit, said contacts being connectable in an electrically conducting manner to the two coil terminals.
Such a data carrier as described in the opening paragraph, such a module as described in the second paragraph and such an integrated circuit as described in the third paragraph are marketed by the applicant and are therefore known. In the known embodiments, the value of the integrated main capacitor which, together with a coil, is provided to form a resonant circuit for contactless communication with a communication system, is in a more or less large range of tolerances. The tolerance range of the integrated main capacitor results from manufacture-related aspects and plays a very important role in the system behavior and the efficiency of a data carrier during communication, because the efficiency is severely affected at a resonance frequency deviating from a desired nominal resonance frequency of the resonant circuit constituted by the main capacitor and the coil. This deterioration of the efficiency is a drawback. A possible measure of obviating this problem is the separation or selection of integrated circuits for a data carrier whose resonance capacitance does not have a desired capacitance of the integrated main capacitor, which, however, leads to a reduced output, which is a drawback and therefore undesirable.
It is an object of the invention to eliminate the above-mentioned drawbacks and to provide an improved data carrier, an improved module and an improved integrated circuit for a data carrier.
To solve the object mentioned above, a data carrier as described in the opening paragraph can be characterized as follows.
A data carrier comprising a coil with two coil terminals and an integrated circuit, said integrated circuit comprising an integrated main capacitor which is connected to two contacts of the integrated circuit, each contact of said two contacts being connected in an electrically conducting manner to a coil terminal via an electrically conducting connection, the integrated circuit also comprising at least one integrated additional capacitor which is connected to at least one additional contact of the integrated circuit, each additional contact of said at least one additional contact being connected in an electrically conducting manner to a coil terminal via an electrically conducting connection.
To solve the object stated above, a module of the type described in the second paragraph can be characterized as follows.
A module comprising coil terminals to which a coil is connectable, which module comprises an integrated circuit, said integrated circuit comprising an integrated main capacitor which is connected to two contacts of the integrated circuit, each contact of said two contacts being connected in an electrically conducting manner to a coil terminal via an electrically conducting connection, the integrated circuit also comprising at least one integrated additional capacitor which is connected to at least one additional contact of the integrated circuit, each additional contact of said at least one additional contact being connected in an electrically conducting manner to a coil terminal via an electrically conducting connection.
To solve the above-mentioned object, an integrated circuit as described in the third paragraph can be characterized as follows.
An integrated circuit for a data carrier comprising a coil with two coil terminals and an integrated circuit, said integrated circuit comprising an integrated main capacitor which is connected to two contacts of the integrated circuit, each contact of said two contacts being connected in an electrically conducting manner to a coil terminal via an electrically conducting connection, the integrated circuit also comprising at least one integrated additional capacitor which is connected to at least one additional contact of the integrated circuit, each additional contact of said at least one additional contact being connectable in an electrically conducting manner to a coil terminal via an electrically conducting connection.
By virtue of the characteristic features of the invention, it is achieved in a relatively simple way that the tolerance range of the capacitance of the integrated resonance capacitor can be restricted so that the resonance frequency determined by this capacitance is always very near a desired nominal value.
In the embodiments according to the invention, it has been proved to be advantageous when the characteristic features as defined in claims 2, 5 and 8, respectively, are additionally provided. In this way, a very accurate and fine-tuned determination of the capacitance of the integrated main capacitor proximate to the desired nominal value is possible.
In the embodiments according to the invention, it has further proved to be very advantageous when the characteristic features as defined in claims 3, 6 and 9, respectively, are additionally provided. In this way, it is achieved that a minimal number of additional contacts is sufficient.
These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter.